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				<h4>第一种方法</h4>
				<pre>
	.drop{
		border: 4px solid transparent;
		border-top: 4px solid #0dafd2;
		display: inline-block;
		margin-left: 10px;
		vertical-align: middle;
	}		
			
	<span class="drop"></span>	
	<style type="text/css">
		.drop{
			border: 15px solid transparent;
			border-top: 15px solid #0dafd2;
			display: inline-block;
			margin-left: 10px;
			vertical-align: middle;
		}
	</style>	
				</pre>
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				<h4>第二种方法</h4>
				<pre>
	.dd{
		border-width: 10px;
		border-style: solid;
		//关键一步，第一个显示的向下的三角形颜色，第二个是右边，第三个是下面向上，第四个是左边
		border-color: #ff2f2f transparent transparent transparent;
		display: inline-block;
		margin-left: 10px;
	}		
			
	<span class="dd"></span>	
	<style type="text/css">
		.dd{
			border-width: 10px;
			border-style: solid;
			border-color: #ff2f2f transparent transparent transparent;
			display: inline-block;
			margin-left: 10px;
		}
	</style>	
				</pre>
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